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#!/bin/sh -e #-e 表明。若指令传回值不等于0，则立即退出shell# shellcheck disable=SC1091#相对路径执行脚本. ../../utils/sh-test-libOUTPUT="$(pwd)/output"RESULT_FILE="${OUTPUT}/result.txt"export RESULT_FILEITERATION="5"usage() {    echo "Usage: $0 [-p 
   
    ] [-t 
    
     ] [-i 
     
      ] [-s 
      
       ]" 1>&2    exit 1}#通过while parse 可选参数while getopts "p:t:i:s:" o; do  case "$o" in    # The current working directory will be used by default.    # Use '-p' specify partition that used for dd test.    p) PARTITION="${OPTARG}" ;;    # CAUTION: if FS_TYPE not equal to the existing fs type of the partition    # specified with '-p', the partition will be formatted.    t) FS_TYPE="${OPTARG}" ;;    # You may need to run dd test 4-5 times for an accurate evaluation.    i) ITERATION="${OPTARG}" ;;    s) SKIP_INSTALL="${OPTARG}" ;;    *) usage ;;  esacdone#定义shell 函数prepare_partition() {	#-n 表示存在partition    if [ -n "${PARTITION}" ]; then		#通过blkid 输出的结果中查找PARTITION        device_attribute="$(blkid | grep "${PARTITION}")"		#如果没有找到PARTITION，则输出错误日志        [ -z "${device_attribute}" ] && error_msg "${PARTITION} NOT found"		#找到这个PARTITION的文件系统fs的类型        fs_type=$(echo "${device_attribute}" \            | grep "TYPE=" \            | awk '{print $3}' \            | awk -F '"' '{print $2}')        # If PARTITION specified, its FS_TYPE needs to be specified explicitly.		# 文件系统类型不存在的话，输出错误日志        [ -z "${FS_TYPE}" ] && \            error_msg "Please specify ${PARTITION} filesystem with -t"        # Try to format the partition if it is unformatted or not the same as        # the filesystem type specified with parameter '-t'.		        if [ -n "${FS_TYPE}" ]; then            if [ "${FS_TYPE}" != "${fs_type}" ]; then				#如果这个PARTITION的文件系统的类型和用户指定的不一致，则umount 掉这个PARTITION                umount "${PARTITION}" > /dev/null 2>&1                info_msg "Formatting ${PARTITION} to ${FS_TYPE}..."				#根据用于指定的文件系统重新格式化PARTITION，这里可以看出fat32 这种文件系统的				#格式化命令和其他的文件系统不同                if [ "${FS_TYPE}" = "fat32" ]; then                    echo "y" | mkfs -t vfat -F 32 "${PARTITION}"                else                    echo "y" | mkfs -t "${FS_TYPE}" "${PARTITION}"                fi                info_msg "${PARTITION} formatted to ${FS_TYPE}"            fi        fi         # Mount the partition and enter its mount point.		 #通过df 命令看是否可以找到mount point         mount_point="$(df |grep "${PARTITION}" | awk '{print $NF}')"         if [ -z "${mount_point}" ]; then			#如果找不到mount point的话，则mount到/mnt             mount_point="/mnt"             mount "${PARTITION}" "${mount_point}"             info_msg "${PARTITION} mounted to ${mount_point}"         fi		 #进入这个目录准备测试         cd "${mount_point}"    fi}#定义一个shell函数用于写测试dd_write() {    echo    echo "--- dd write speed test ---"	#删除这个文件    rm -f dd-write-output.txt	#测试的partition 可能有多个，这里用for 循环    for i in $(seq "${ITERATION}"); do        echo "Running iteration ${i}..."		#删除文件        rm -f dd.img		#drop cache        echo 3 > /proc/sys/vm/drop_caches		#执行dd 命令开始写测试        dd if=/dev/zero of=dd.img bs=1048576 count=1024 conv=fsync 2>&1 \            | tee  -a "${OUTPUT}"/dd-write-output.txt    done}#定义一个shell函数用于读测试，这个函数和写函数操作类似dd_read() {    echo    echo "--- dd read speed test ---"    rm -f dd-read-output.txt    for i in $(seq "${ITERATION}"); do        echo "Running iteration ${i}..."        echo 3 > /proc/sys/vm/drop_caches        dd if=dd.img of=/dev/null bs=1048576 count=1024 2>&1 \            | tee -a "${OUTPUT}"/dd-read-output.txt    done    rm -f dd.img}parse_output() {    test_case_id="$1"	#如果不存在文件，则输出警告并通过return 退出    if ! [ -f "${OUTPUT}/${test_case_id}-output.txt" ]; then        warn_msg "${test_case_id} output file is missing"        return 1    fi    itr=1	#逐行读取    while read -r line; do        if echo "${line}" | egrep -q "(M|G)B/s"; then            measurement="$(echo "${line}" | awk '{print $(NF-1)}')"            units="$(echo "${line}" | awk '{print substr($NF,1,2)}')"            result=$(convert_to_mb "${measurement}" "${units}")            add_metric "${test_case_id}-itr${itr}" "pass" "${result}" "MB/s"            itr=$(( itr + 1 ))        fi	#从这个文件中读取    done < "${OUTPUT}/${test_case_id}-output.txt"    # For mutiple times dd test, calculate the mean, min and max values.    # Save them to result.txt.    if [ "${ITERATION}" -gt 1 ]; then		#用eval 执行字符串中的内容，为啥不直接执行呢？        eval "$(grep "${test_case_id}" "${OUTPUT}"/result.txt \            | awk '{                       if(min=="") {min=max=$3};                       if($3>max) {max=$3};                       if($3< min) {min=$3};                       total+=$3; count+=1;                   }               END {                       print "mean="total/count, "min="min, "max="max;                   }')"		#输出测试结果        # shellcheck disable=SC2154        add_metric "${test_case_id}-mean"  "pass" "${mean}" "MB/s"        # shellcheck disable=SC2154        add_metric "${test_case_id}-min" "pass" "${min}" "MB/s"        # shellcheck disable=SC2154        add_metric "${test_case_id}-max" "pass" "${max}" "MB/s"    fi}# Test run.#检查是否是root用户! check_root && error_msg "This script must be run as root"create_out_dir "${OUTPUT}"info_msg "About to run dd test..."info_msg "Output directory: ${OUTPUT}"#安装这两个toolpkgs="e2fsprogs dosfstools"install_deps "${pkgs}" "${SKIP_INSTALL}"#准备要测试的partitionprepare_partitioninfo_msg "dd test directory: $(pwd)"#dd写测试dd_writeparse_output "dd-write"#dd读测试dd_readparse_output "dd-read"
      
     
    
   

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